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Calculating Machines

Maker Index

Calculating machines were known by the names of inventor (Baldwin, Barbour, Bolleé, Grant), famous mathematicians (Archimedes), desired characteristics (Millionaire, Rapid), and investors (Monroe). The following list makes it easier to see related products. Trade names are used instead of company names as these show up most frequently on objects.

This is an early model of the full-keyboard, modified stepped drum, manually operated non-printing calculating machine manufactured by the Monroe Calculating Machine Company on patents of Frank S. Baldwin.

The machine has a steel frame painted black. The eight columns of plastic keys are colored black or white according to the place value of the digit represented. The key stems are banked, standing up further toward the back of the machine. At the front of the keyboard is a row of red keys each of which clears the column above it. On the right side, in this row, is a red key for clearing the entire keyboard. There are no strips between columns of keys. Two silver-colored knobs have arrows on them. The one on the right is used for automatic keyboard release in continuous addition. The one on the left is the register key for the item counter.

In back of the keyboard is a carriage with 16 black total register dials and eight revolution register dials behind the total dials. The dials of the revolution register are numbered around the edge from 9 to 0 white and from 9 to 1 in red. The metal operating handle with a wooden knob painted brown is on the right side. Another handle on the right side of the carriage zeros the total register or the revolution register, depending on the direction in which it is turned. There is no knob to lift the carriage. An all-metal crank at the front of the machine is rotated to move the carriage. The carriage has sliding decimal markers for both registers.

The machine is marked at the center of the back edge, underneath the carriage: 20. A mark on the front reads: MONROE (/) Calculating Machine Company (/) New York. There is no mention of a trademark. A sticker on the back reads: PATENTED JUNE 16, 1908 (/) OTHER U.S. AND FOREIGN PATENTS (/) PENDING.

Compare to MA*317389. Both machines have the same number of keys, the same number of entries in the revolution counter and result registers, and the same mark on the sticker on the back. The mark on MA*317389 mentions a trademark. The color-coding of the keys, the color of the machine handles and shift lever, and the mechanism for the carriage shift differ between the machines. Object MA*317389 has rotating rods that serve as decimal dividers on the keyboard, and a considerably larger serial number, which begins with a D. Hence that machine is given a slightly later date.

This lever-set non-printing pinwheel duplex calculating machine has six levers that are rotated forward to set digits from 0 to 9. The pinwheels that carry out arithmetic operations are not beneath the levers but in a separate row of wheels in back of them. The machine has a lever at the right bottom front and a crank for shifting the carriage at the center front. The set-up mechanism has two sliding decimal markers.

Behind this mechanism is a large carriage that has a row of 12 result dials at the front, a row of 14 result dials behind this, and a revolution register with seven dials behind these. These dials each have 20 digits around the edge. Alternate digits are for problems in addition and multiplication and for problems in subtraction and division. The windows showing the dials may be set to show either sets of digits. The revolution register has a carry mechanism. Both result registers have sliding decimal markers. Wheels used to set up numbers are between the dials of the result registers. The operating crank is on the left. Two rods are on both the right and the left side of the carriage.

The machine has an extremely heavy steel frame and mechanism. The outside is covered with a layer of silver-colored metal stamped with a small foliate pattern. A mark on the front reads: MONOPOL. A mark on the left side of the carriage reads: A.M. A mark on the right side of the carriage reads: S.D. The serial number, 367, is on a crosspiece visible only when the carriage is lifted.

According to Martin, this was the first pinwheel calculating machine with tens-carry in the revolution register. Monopol machines reportedly were manufactured between 1894 and 1914.

This lever-set, non-printing, and manually operated pinwheel calculating machine has a metal housing painted black, a steel mechanism, and nine levers for entering numbers. At the top left is a small metal lever. A steel operating crank with a wooden handle extends from the right side of the machine. The crank rotates backward (clockwise) for addition and multiplication and forward (counterclockwise) for subtraction and division. A wing nut on the left side zeros the setting levers.

A movable carriage at the front of the machine has 13 windows that show dials of the result register on the right and eight windows for the revolution register on the left. The revolution register has no carry mechanism. The digits on the revolution register dials are white for additions and red for subtractions. A narrow metal rod carries decimal markers for the revolution and result registers. Depressing a lever at the front of the machine releases the carriage for shifting. Rotating wing nuts at the ends of the carriage zero the registers on it. A bell on the left end of the carriage rings when the result passes through zero.

Three marks on the front of the machine read: BRUNSVIGA; No 14544; and CARL H. REUTER (/) LAND TITLE BUILDING (/) PHILADELPHIA, PA. A mark painted on the front of the machine, on the case, and twice on the back reads: UC-CE-C; U.S.E.D. A fifth mark, with an elaborate drawing, is on the back of the machine and reads: BRUNSVIGA (/) REGISTERED TRADE MARK. A mark on the back of the machine reads: PATENTED IN THE UNITED STATES, 12 JUNE 1906.

The case has a wooden base and a metal lid painted black, with a broken lock and leather handle at the front. A mark on it reads: „Brunsviga.”

Compare MA*315904.

This machine came to the Smithsonian from the Office of the Chief of Engineers of the Department of the Army in 1950.

This is an early model of the full-keyboard, modified stepped drum, manually operated, non-printing calculating machine manufactured by the Monroe Calculating Machine company on patents of Frank S. Baldwin.

The machine has a steel frame, painted black. The eight columns of plastic keys are colored black or white according to the place value of the digits represented. The key stems are banked, standing up further toward the back of the machine. At the front of the keyboard is a row of red keys, each of which clears the column above. On the right side, in this row, is a red key for clearing the entire keyboard.

Behind each column of keys is a double disc with teeth of varying length protruding from it that serves as a stepped drum. One disc has five teeth on it, and the other has four. Pushing the appropriate key causes one or both of the discs to approach one another so that they are engaged when a crank on the right side turns, entering the appropriate number into the mechanism.

Between the rows of keys are metal strips, painted black on one side and white on the other. They rotate to serve as decimal markers. Two silver-colored knobs have arrows on them. The one on the right is used for automatic keyboard release in continuous addition. The one on the left is the register key for the item counter.

In back of the keyboard is a carriage with 16 black total register dials and eight white and red revolution register dials behind the total dials. Between the windows for these registers are two thin metal rods that carry decimal markers. Another handle on the right side of the carriage zeros the total register or the revolution register, depending on the direction in which it is turned. A knob on the right side of the carriage is used to lift it. A crank at the front of the machine rotates to move the carriage.

A mark on the front of the machine reads: MONROE (/) REGISTERED TRADEMARK (/) Calculating Machine Company (/) New York, U.S.A. A sticker toward the left on the carriage reads in ink: CLEARING. A mark at the center of the back reads: D1749. A mark under the carriage on the right reads: 1749. A sticker on the back of the machine reads: PATENTED JUNE 16, 1908 (/) OTHER U.S. AND FOREIGN PATENTS (/) PENDING.

Compare MA*307385. The latter machine has a different carriage shift mechanism, a lower serial number, and a different color-coding of the keys. It has no decimal dividing rods between the keys, and no mention of a trademark. It has a different way of marking decimal divisions on the carriage and has been assigned a slightly earlier date.

Monroe first used the name Monroe to describe its products in 1913. The company applied for a trademark on April 7, 1919, and was granted it onJanuray 20, 1920.

This stepped drum manual non-printing calculating machine has a brass top that fits closely into a roll-top wooden case. The top is stuck and cracked at the front. The seven German silver levers on the machine (another one is missing) are rotated counterclockwise to set digits. The number entered appears in a row of windows over the levers.

Above this is a steel rod with one sliding decimal marker. The operating handle is right of the levers. The zeroing lever for the entry and the addition & multiplication / subtraction & division lever are left of the levers. Left of this is a small empty compartment with room for an inkwell and cover.

Behind the levers is a carriage with nine revolution register windows and 16 result register windows. Both registers have thumbscrews for setting numbers and two decimal markers that slide on steel rods. The revolution register does not carry as numbers are added. When the entry in the result register would become negative (as it might in subtraction or division), a bell rings. It rings again if a number is added so the result is once again zero or positive. There are four rubber feet. The brass stepped drums are visible through a sliding panel in the bottom of the case. Metal lifting handles are on both ends of the machine.

The machine is marked above the entry levers: REUTER’S (/) MULTIPLYING AND DIVIDING MACHINE (/) PHILADELPHIA,PA. It is marked on metal tags near the front of the case: D.R.G.M. 394014 and: AUSL. PAT. ANGEM. It is marked under the crank: D.R.G.M. (/) 329403. It is marked to the left of the entry levers: PATENT (/) GERMANY. The serial number marked below the carriage on the left side of the machine and at the center back edge of the case is 3100. A slip of paper under the glass is marked: Received for trial MAY 27 1913 (/) overhauled (/) and (/) returned June 4 1922.

This is an example of the Saxonia calculating machine, made by Schumann and Company in the German city of Glasshütte, and imported and distributed by the Philadelphia firm of Carl H. Reuter. It is from the collection of Felt & Tarrant Manufacturing Company.

This relatively late English-built arithmometer represents C. & E. Layton's improvements to the machine originally designed by Samuel Tate. The stepped drum manually operated non-printing calculating machine has a brass and steel mechanism attached in a mahogany case.

The eight setting levers are above a row of windows that show the number set. The zeroing lever for the setup is on the right and an ADD-MULT / SUB DIV lever is on the left. The crank for operating the machine is right of the levers. Below it is zeroing lever for the entry levers. The stepped drums are brass.

The carriage has 9 windows in the revolution counter register and 16 in the result register. On the right of the carriage is a crank that is turned counterclockwise to zero the revolution register and clockwise to zero the result register. When the entry in the result register would become negative (as it might in subtraction or division), a bell rings. It rings again if a number is added to bring the total to zero or more.

The Mercedes-Euklid calculating machine has a distinctive mechanism. Moving a lever or pushing a key engages a toothed gear with one of a series of ten parallel toothed racks that move crosswise when the crank is turned. The amount a rack moves varies according to its distance from the back rack. A rod, called a proportional rod, pivoted along this rack controls this motion. The amount a rack moves determines the motion of gears linked to it, and hence the number entered.

This manually operated and lever-set proportional rod calculating machine has a black steel frame and a steel base. Nine levers are used to set numbers, with a row of windows below that shows the number set. To the right of the levers is the operating crank. In front is a carriage that can be moved when a release button to the left of the setting levers is pushed. The carriage has eight numeral wheels for recording revolutions of the crank, and 16 numeral wheels for recording results. The numeral wheels are covered with glass.

Numbers also may be set in the result register by rotating thumbscrews in the front of the carriage. They are used to set a dividend. Below the thumbscrews are knobs for zeroing the revolution counter and result register. To the left of the setting levers and carriage release button are two levers. One may be set at N or C. When it is set at N, the number in the revolution register increases by one whenever the crank is rotated. When it is at C, one rotation leads to subtraction in the revolution register. The other lever may be set at ADD.MULT or SUBT.DIV., depending on the arithmetic operation desired.

A mark on the top of the machine reads: MERCEDES-EUKLID. The serial number, given below the carriage at the left, is 1020. A mark on the carriage reads: MERCEDES-BUREAU-MASCHINEN-GES.m.b.H. [/] MEHLIS i.TH.u.BERLIN W.

Christian Hamann of Berlin patented this machine, and it was manufactured in Germany from about 1905. This example came from the collection of Felt & Tarrant Manufacturing Company.

This full-keyboard manually operated non-printing modified stepped drum calculating machine has a steel frame painted black. The eight columns of round plastic keys are colored black or white according to the place value of the digit represented. The key stems are banked, standing up further toward the back of the machine. A row of red clearance keys is at the front of the keyboard; a red key for clearing the entire keyboard is on the right side. Between rows of keys are metal strips, painted black on one side and white on the other, that turn to serve as decimal markers. Ther two silver-colored knobs have arrows on them. One on the right is used for automatic keyboard release in continuous addition. One on the left is the register key for the item counter.

A carriage behind the keyboard has 16 black total register dials and eight white revolution register dials. The revolution register has black digits for addition and red ones for subtraction. A metal operating handle with a wooden knob is on the right side. Another handle on the right side of the carriage zeros the total register or the revolution register, depending on the direction in which it is turned. A knob on the right side of the carriage is used to lift it. A crank at the front of the machine rotates to move the carriage. The machine has four rubber feet.

A partly obliterated mark on the front reads: MONROE (/) REGISTERED TRADEMARK (/) Calculating Machine Company (/) New York, U.S.A. A mark in the middle of the back of machine reads: E5681.

This particular machine came to the Smithsonian from Feldman’s Department Store in Baltimore, Maryland, when the then fifty-year old family business was liquidated in 1974.

According to McCarthy, Monroe began manufacturing the Model E in 1916, using serial numbers beginning at 4,000. Monroe received a registered trademark for its machines in 1920, and began marking objects to that effect. In 1921 it replaced its earlier models with the model K. Hence the date assigned.

This compact pinwheel lever-set manually operated non-printing calculating machine has a a steel mechanism and housing partly painted black. It has nine slots with levers for setting numbers. The levers rotate forward to set digits. A steel crank with a wooden handle that extends from the right side of the machine rotates backward (clockwise) for addition and multiplication and forward (counterclockwise) for subtraction and division. A wing nut on the left side zeros the setting levers.

At the front of the machine is a movable carriage with 13 windows that show dials of the result register on the right and eight windows for the revolution register on the left. The revolution register has no carry. Digits in this register are white for addition and red for subtraction. The sliding decimal markers are on a rod over the result and revolution registers.

Depressing a lever at the front of the machine releases the carriage for shifting. Rotating the wing nuts at the ends of the carriage zeros the registers on it. A bell is on the left end of the carriage.

Marks on the front of the machine read: BRUNSVIGA-MIDGET; No 25209; and PATENT (/) G.N.& C.C.a.A. A mark on the back of the machine at the bottom reads: Patented in the United States 12 June 1906.

The wooden case has a flat base and curved lid, with a handle, a lock, and a key on the right side.